THE STOMACH. 



159 





Interglandulai 

 tissue 



the entire thickness of the mucosa and abut against the muscularis mucosae. 

 Each gastric crypt corresponds to an excretory duct and receives several oi 

 the tubules, in which the neck, body and fundus of the gland are recognized. 

 The slightly constricted neck marks the transition of the columnar epithelium 

 lining the crypt, prolonged from the free surface, into the gland-cells. The 

 latter are of two kinds, the chief and the parietal. The chief cells, called also 

 central or adelomorphous, are clear low cylindrical or cuboidal elements that 

 line the tubule and surround a narrow but distinct lumen. Their spherical 

 nuclei occupy the central part of the 

 clear cytoplasm that sometimes (dur- 

 ing rest) is filled with secretion or 

 zymogen granules and at other times, 

 after the granules have disappeared, 

 shows a distinct reticulum. These 

 elements, often imperfectly preserved, 

 are probably concerned in producing 

 pepsin. The parietal cells, known 

 also as acid, oxyntic or delomor- 

 phous, although relatively few are 

 conspicuous by reason of their size, 

 peripheral position (Fig. 198) and 

 selective affinity for certain stains. 

 They are large, of rounded triangular 

 form, and lie immediately beneath the 

 basement membrane, which often 

 displays in profile an outward bulg- 

 ing as it passes over the cell. The 

 finely granular cytoplasm encloses a 

 distinct spherical nucleus that may 

 be double. Although arranged with 

 little regularity, the parietal cells are 

 most numerous towards the neck of 

 the tubule, where they may form an 

 almost unbroken layer; they decrease 

 in number on approaching the fundus, 

 in which they are few or wanting. 

 While excluded by the chief cells 

 from contact with the lumen of the 

 tubule, the parietal cells are connected 

 with the central cleft by means of 



lateral channels, the secretion-canaliculi, that pass outwards between 

 chief cells and enclose the parietal cells with networks. 



The pyloric glands differ from the fundus glands in the excessive width 

 and depth of their crypts, the excretory ducts, into which groups of relatively 

 short tortuous gland-tubules open, and in the character of their lining cells. 

 The latter are almost exclusively columnar or pyramidal elements which 

 resemble the chief cells of the fundus glands. That, however, they are at 

 least functionally different is shown by their behavior with certain stains, as 

 well as by the mucus reaction of their secretion. The spherical nuclei com- 

 monly lie near the basement membrane. Occasional parietal cells are also 

 present. Owing to their tortuous course, the deeper parts of the pyloric 

 tubules, when viewed in sections, are cut in various planes. Within the 

 intermediate zone between the pyloric and adjoining portions of the stomach, 



Parietal cell 



FIG. 198. Deep portions of gastric glands from 

 fundus, showing the two varieties of lining cells 

 and secretion-canaliculi connecting parietal cells 

 with the gland-lumina. X 315. 



the 



